Moving laser beam readers or laser scanners have long been used to electro-optically read one- and two-dimensional bar code symbols. The moving laser beam reader generally includes a housing, a laser for emitting a laser beam, a focusing lens assembly for focusing the laser beam to form a beam spot having a certain size at a focal plane in a range of working distances relative to the housing, a scan component for repetitively scanning the beam spot across a target symbol in a scan pattern, for example, a scan line or a series of scan lines, across the symbol multiple times per second, a photodetector for detecting light reflected and/or scattered from the symbol and for converting the detected light into an analog electrical signal, and signal processing circuitry including a digitizer for digitizing the analog signal and a microprocessor for decoding the digitized signal based upon a specific symbology used for the symbol. Generally, laser scanners can be operated in a handheld mode or in a stationary workstation mode.
Solid-state imaging systems or imaging readers have also been used to electro-optically read such symbols. The imaging reader includes a housing, a solid-state imager or sensor having an array of cells or photosensors, which correspond to image elements or pixels in a field of view of the imager, an illuminating light assembly for illuminating the field of view with illumination light from an illumination light source, e.g., a laser or one or more light emitting diodes (LEDs), and an imaging lens assembly for capturing return ambient and/or illumination light scattered and/or reflected from the symbol being imaged over a range of working distances. Such an imager may include a one- or two-dimensional charge coupled device (CCD) or a complementary metal oxide semiconductor (CMOS) device and associated circuits for producing electronic signals corresponding to a one- or two-dimensional array of pixel information over the field of view. Signal processing circuitry including a microprocessor processes the electronic signals to decode the symbol. An aiming light generator may also be provided in the housing for projecting an aiming light pattern or mark on the symbol prior to imaging. Like laser scanners, solid-state imaging scanners can also be operated in a handheld mode or in a stationary workstation mode.
FIG. 1 generally depicts an optical barcode scanner 40 that can be operated in both the handheld mode and the workstation mode. The optical barcode scanner 40 includes a window 46, a trigger 41, a housing 42, and a base 48. The electrical power to the electronic components in the optical barcode scanner 40 can be supplied via a cable connected to the housing, or via a battery in the housing. The base 48 can function as a support for the optical barcode scanner 40 when it is placed on a flat surface. The optical barcode scanner 40 can thus be used as a stationary workstation, when it is placed on a countertop and products are slid or swiped past the window 46. The optical barcode scanner 40 can also be used as a handheld reader, when it is held in the operator's hand after being picked up off the countertop and the trigger 41 is manually depressed to initiate reading of barcode symbols.
Barcode scanners like the optical barcode scanner 40 in FIG. 1 have been quite successful for many years and have been used widely in many barcode applications. It is desirable to add other kind of data capture capabilities to these barcode scanners in a modular and cots effective manner.